Many engines utilize a throttle valve to control or throttle air flow to the engine in accordance with a demand on the engine. Such throttle valves may be used, for example, in throttle bodies of fuel injected engine systems and in carburetors of carbureted engine systems. Many such throttle valves include a valve head carried on a shaft that is rotated to change the orientation of the valve head relative to fluid flow in a passage, to vary the flow rate of the fluid in and through the passage. Other applications also use components that rotate, and the position of these components may need to be known for feedback control or other reasons.